Acid Burn
by QuirkQuartz
Summary: During a training exercise, Ashido accidentally ends up hitting Izuku with her Quirk. When Recovery Girl isn't at her post, she takes it upon herself to treat his wound, swapping from a panicked persona, to a more solemn one in the course of five minutes, leaving Izuku with one question - What is going through her head?


"I'm so freaking sorry, Midoriya!"

"A-Ashido, I-I'm fine, j-just calm down and – "

"This is _not_ the time to be calm! Just keep your hand under that cold water and lemme find some stuff!"

The pink skinned girl rummaged through every single cupboard and drawer that she could find, frantically searching anything that she would be able to use, stopping short of just throwing everything else out of their storage compartments so she could easily reach whatever it was that she was trying to get from each individual compartment. Izuku got the distinct feeling that Recovery Girl wasn't going to be happy when she checked on her supply, and found it all knocked over, disorganized, mixed up and a downright mess, but Ashido wasn't in any sort of frame of mind to care.

Recovery Girl wasn't at her usual station, apparently having to deal with an incident regarding third Year students that had injured one another during a training exercise, leaving Izuku and Ashido with no one professional to treat the green haired boy's injury.

So Ashido had just decided to do it herself.

"Come on, come on…" She muttered to herself, pushing various other bottles of treatments aside, knocking some outright onto the floor, protected only by their cardboard casing, and mixing up whatever was left. At several points, she rose onto her toes and reached further into the back of the storage lots, relying primarily on her sense of touch to help her find what she was looking for. Easy when she was trying to get bandages, not so much use when she was trying to find disinfectant.

Based on how much she seemed to know about what she was doing here, Izuku had a feeling that this wasn't the first time that something like this had happened. Perhaps accidents involving her Quirk were common. She seemed to have a very clear idea on what she was looking for, becoming visibly distressed when she wasn't able to locate it.

A mere three items were all but slammed right in front of Izuku with such force that he almost thought that the table was going to snap in half. These items were a set of water-based painkillers, some disinfectant in a bottle marked 'Peroxide', to the side of which was some tissue paper that had come with the packaging, and a roll of dressing bandages that were already slightly unravelled.

"I gotta grab something from another room." The panic that Ashido was displaying was bizarre, and uncharacteristic of the normally cheerful and carefree girl. Guilt and fear seemed to have washed over her entire being, while she ran around, and towards the door, desperate to get what was needed to fix the mess she'd made. "Just – Just keep your arm under that running water, and I'll be right back!"

Before Izuku even had a chance to respond, she was gone, already charging down the corridor to who even knew where, to grab who even knew what, leaving her patient sat there, eyes wide open, still confused as to the nature of her behaviour.

Well, he wasn't exactly confused as to why. It made sense as to why she was worried, and on edge. That wasn't what confused him.

After all, this was her fault.

It had been a regular training session for everyone in Class 1A, and was akin to a simple game of capture the flag. Two students would form a team, based on a random name generator, and they would go up against everyone else in the class. This team was the "Hero" Team, while everyone else was the "Villain" Team. The objective of the Hero Team was to grab hold of the 'Flag', which in this case was a dummy that was being used in place of a civilian, and return it to their starting point, preferably with the dummy still intact, and not at all injured.

On the surface, it was a very simple training exercise, if one that was dramatically stacked against the Hero Team. The Dummy was always in the same place, meaning that the Villain Team would be able to set a number of ambushes around the target, and would always know where their enemies would be aiming to go. That was the whole point though. Often times, the odds were stacked against the Heroes, and it was the ability to overcome those dangers, and push back against those odds, that made a true Hero.

The teams had been completely randomized. Uraraka and Ojiro, Mineta and Tokoyami, Kirishima and Hagakure, Tsuyu and Bakugou, and so on and so forth. People who normally wouldn't pick one another to fight alongside in many cases, which did lead some of them to think that the results weren't randomized at all, but instead chosen to force students who wouldn't normally work together to do so, mostly to make them consider Quirk synergization.

Izuku had been paired up with Ashido, in a team that neither had expected, but neither rejected the idea either. Despite their lack of interactions until this point, both had a generally positive opinion of the other one. The main issue in this case was the fact that their Quirks were quite possibly the least compatible set in the entire class. Acid, which belonged to Ashido, was a Quirk that coated her opponents with the deadly substance that she secreted, eroding and evaporating until there wasn't anything left of the liquid. An extremely powerful Quirk on its own, but in terms of teamwork, it was a huge hindrance to those she worked with. Izuku's own One For All power, known only to his classmates as a Strength Enhancer, relied on physical contact with his enemies – Something which, when combined with Ashido's Quirk, was basically like asking him to get burned.

Which was exactly what had happened.

Of course, they had tried to be careful, to set things up so that this wouldn't happen. They had decided that Ashido would be the person to act on guard, to defend Izuku while he acquired the target. Izuku's Quirk was going to be needed to make a quick exit once they had the Dummy. The plan was to sneak their way there as much as possible, fight through whoever saw them and tried to stop them, get the Dummy to Izuku, and then he would dart right out of the fight, leaving Ashido behind while he ran for the exit – As long as the Dummy got to the exit, then they would have succeeded. No one would really bother trying to contain Ashido, since at that point, there was no reason to do so. They would charge right for Izuku, trying to stop him from reaching the boundary line.

That had been the plan.

Long story short, their entire strategy fell apart basically upon first contact. Since they were still trying to acquire their target, Izuku was still ready to use his power for fighting. When they encountered their first opponent – Kirishima – He had gotten ready to leap forward, to land whatever strike he could against the Hardening Quirk user.

Ashido had the exact same idea, only she had generated acid around her forearms. Kirishima had a Hardening Quirk, so he would have high defensive capabilities. Acid would burn right through that without injuring him. But since she had no way to manipulate the substances that she generated, she couldn't stop the inevitable collision between the two of them. Couldn't de-active her Quirk to stop the impact. And couldn't call out to warn him in time. Momentum was already in motion.

The only thing to do was to just watch in horror as it happened.

About a third of Izuku's right forearm was covered in first degree hydrofluoric burns, which was how they had wound up in the infirmary in the first place. Since Recovery Girl wasn't there, Ashido had taken it upon herself to heal the injury, or at least treat it before it became any worse than it already was, prevent infection, and whatever else she could think of doing. In her panic, she hadn't even bothered to ask if the wound had caused Izuku any serious, chronic pain.

It hadn't. It stung, and had burned a large portion of his forearm, but it wasn't immeasurable pain, or anything that he hadn't felt before. He'd suffered plenty of worse injuries at the hands of people who were legitimately trying to kill him that, and shattered his own bones into oblivion thanks to his own power. He was used to pain, had a high tolerance to it, and had adapted to it to a certain extent. It took a lot to make him seriously feel an injury after being through so much beforehand.

While her Acid Quirk was certainly potent, and had hurt a lot, she had used a weaker concoction of her power. The pain was bearable, more akin to a burn that one might get if they had bleach applied to a sensitive scalp. It would recover with time, and wasn't anything too major to worry about.

But Ashido hadn't even thought to ask, and had practically dragged him to the infirmary immediately for first aid treatment.

Seeing her like this was a weird, eye opening experience for Izuku. He had been under the distinct impression that she was the sort of person who went with the flow of things, allowed them to happen as they did, and accepted when she made mistakes and moved on. She didn't seem like the type to panic over those mistakes. Injuring a fellow student, he could understand her showing concern and showering him in a torrent of apologies. He could understand her going with him to the infirmary to make sure that he was okay.

But wasn't this going a little bit above and beyond? In the normal event of an injury like this, Izuku would be taken to the infirmary by either a staff member, or the robots that Yuuei had installed all across the campus to deal with various situations as they arose, dependant on the level of severity that the severity of the aforementioned injury. Instead, despite it being a relatively minor injury, Ashido had decided that it was way too dangerous to just sit around and wait for the proper, apparently more time consuming methods.

She had displayed above average care for him, and that was what had confused him the most. The two barely even knew one another, had barely even exchanged words, or had spoken at all in the past year, yet here she was.

Why did she care so much? Caring about things that didn't necessarily involve the person in question was something that All Might praised as being Heroic, that much was true, but this just…. Felt different. It wasn't an easy thing to explain, other than the fact that to Izuku, it didn't seem to make a whole lot of sense.

He didn't come to an answer though, before the Acid Quirk user had kicked the door open, and returned into the room, this time in her hands, a large, clear, glass based aquarium, and within it, a box of baking soda.

"W-What the heck, Ashido?!" Izuku couldn't stop himself from vocally questioning what on earth she was even doing at this point. There was only so much that he could take when it came to being clueless about any given situation before he just had to stop everything and get answers to sate his curiosity. Actually, at this point, it was rapidly turning into anxiety based concern. "Wh-Where did you even get that?"

"Support Course Room. Something about liquid based Quirks and learning to control the output better." Came her response, before she placed down the tank on the desk before Izuku, pulled the baking soda out of the empty aquarium, and then put it to one side. "Okay…. Just, wet a towel or something and wrap it around your burn. I need to fill this up with water."

"A-Ashido, you really don't need to do this. I-I'm fine, this isn't – "

"Just… Let me do this."

The tone of her voice made Izuku pause for a moment. She appeared to now be much calmer, but seemed solemn with it. Quieter than her normal energetic, or previously frantic personalities. It was almost jaw dropping.

Had she cooled off after having sprinted down the corridors to the support course room?

Had she taken a breath of air and forced herself to calm down?

Or had she just fully realized what she was doing, and what had happened?

On her face, an expression of shame had taken over, one that Izuku hadn't even managed to see while she had been lugging around the aquarium. Her black eyes were half closed, and her pupils focused solely on what her hands were doing. The sparkle that characterised the horned girl's eyes seemed to have disappeared into nothingness, concealed by a few strands of her unkempt pink hair.

This was a very different Mina Ashido than the one that Izuku had been dealing with just five minutes prior. It almost felt like she was a different person entirely. Almost alien to the Ashido that he knew only in passing before. Whatever had brought this change about had hit her hard, leaving her almost a bit like a husk. Sure, she was able to talk like she was her normal self, but she was terrible at concealing her emotions visually. Naturally, she was an expressive sort of girl, but that was a double edged sword in some cases, such as leaving her unable to hide her feelings when she was down.

Just as panic didn't suit her, and to an even more notable degree, downtrodden and dim expression didn't suit her either. For someone who was normally so bright, it was honestly haunting.

What was going on in her mind?

Even though his concern was now solely focused not on his injury, but on the girl in front of him, Izuku nodded, and did as she requested. Recovery Girl, thankfully, had no shortages of rags and medical supplies, so finding something to wet and wrap around his arm while Ashido ran the tank under the cold cap wasn't difficult. He watched while she then opened the box of baking soda by tearing off the top entirely, and then pouring it into the half-filled cuboid.

"It's a remedy that my mother used whenever something like this happened." Explained the female student, emptying the box before throwing it in the nearest garbage bin, and dusting off her Hero Costume of any powder that had gotten onto her. "When my Quirk first activated, I accidentally hurt my older brother with it. I thought it was just slime. My mother did this and it worked well. It's…. Pretty good for helping to clean out the wound, according to her. It'll sting… Like hell, though." The aquarium now filled with water, she then dragged it back onto the desk, unable to lift it with nearly fifty gallons of liquid inside it. Now in front of Izuku, she then gestured for him to submerge his hand into the solution. "Go for it. It'll help."

Doing as he was instructed, Izuku followed her order, and lowered his hand into the tank. Once the water was level with his wound, he sharply hissed aloud – It stung like salt on a papercut, and his immediate instinct was to pull his hand out of the water. Instead, however, he persevered, and kept, slowly, lowering his arm into the clear liquid, letting out a long series or pain filled groans and hisses as he did so.

"Owwwww…!"

"Okay, now just…. Leave it there for a few minutes." Sighed Ashido, just taking a moment to inhale, and then exhale. Izuku suspected that she hadn't even taken a second to just breathe since this whole event had unfolded.

For a moment, there was nothing but silence between the two of them, the only thing that could be heard was the humming of the air conditioner, the dripping water from the recently turned off tap, and Ashido as she kept breathing in, and then breathing out, trying to regain the oxygen she had lost from darting around the place like her life depended on it. Normally, she had a ton of energy, to the point that it seemed like if she was put onto a treadmill, she could burn enough to power the entire 1A dorm building, and still have plenty left over.

Frankly, the green eyed boy found the silent to be rather awkward. Here he was, with most of his arm submerged in a baking soda – water mix, and the only other person in the room was the person who had put him in this situation in the first place, hunched over a desk, without saying a word. He wanted to say something, to break the tension, but was unsure of what exactly he could say. What could you say to someone who had accidentally hurt you with their Quirk and had been running around the entire school trying to fix it?

What did you say to someone when you didn't know what was going on in their mind?

"I'm…. Uh…" Izuku started, catching the heavily mutated girl's attention. When she looked towards him, that same look of resignation mixed in with her appearance of overall humility and sincerity made his words catch in his throat. "A-hem…" He cleared his throat quickly, before he spoke again, this time, with a lot more clarity. "Um…. Thank you."

"Huh?" Ashido's left eyebrow quirked up in utter confusion, and her right eye seemed to squint at the curly haired boy like he was some kind of masochist. "You… Do realize that I just put you in the infirmary, right? That isn't something that you normally get thanked for."

"N-No, I mean for…. Helping to treat the burn and everything."

"…I'm the one that caused it." She said, quietly, looking towards the ground. Her shoulder slumped, as she let out a small sigh. "You don't really get points for helping if you're the person that caused the problem in the first place."

"I… Still appreciate it though, Ashido. Thank you."

"…Anytime… I'm… Sorry. For, you know, hitting you with my Quirk."

"Don't – Don't worry about it, its okay. I know that it was just an accident. It's just something that happens."

"It's not very Heroic though..." Looking at her palm, Ashido let out a longer, and louder sigh, before allowing her hand to flop to her side, absently swinging. "Not for someone with my kind of Quirk."

"Huh?"

Ashido looked towards Izuku, and then back to looking at the wall in front of her, and then back to Izuku, before sighing for a third and final time. Holding up her previously limp limb, she displayed the pink tint of her skin, an after effect of her Quirk. Her own eyes ran down her limb, like she were inspecting it for irregularities.

"My Quirk lets me secrete Acid, sure… But I can't really control it. Even after all that training when we made our special moves, I can't really direct where my powers will go. I'll end up hurting someone if I'm not careful… And today, I ended up hurting you, because I wasn't careful enough with my power." As she reminded her victim of what she had done to him, she looked away, in shame.

That was what was wrong with her. Why she was acting in all these uncharacteristic ways. Why she had gone from frantic and scared, to solemn and quiet. It was because, in her short time separated from the person that she had ended up hurting, she had been provided time to think clearly, and she had come to a self-degrading conclusion.

She was the one that had screwed up.

She was totally at fault. And now, she was wrecked with guilt for what she had done. Even if it was just an accident, that didn't change that she'd been the one to mess up this badly. She felt that she was better than this, better than what she had done…. But had done it anyway.

She was ashamed of herself. Ashamed that she had been careless, and that she had slipped up so badly that it hurt someone else. She was ashamed, and it had been such a blow to her self-confidence, that she now doubted herself in everything when it came to her unique Quirk.

"Heroes are supposed to be in control of a situation, aren't they?" She continued, speaking now without really thinking about restraining herself. There wasn't really much point in doing so, especially not to the person that she'd ended up hurting in the first place. Especially not this particular person. She probably wouldn't be able to lie to him anyway. She wasn't particularly good at it in the first place. "They use their Quirks to fight Villains and protect people… That's what Heroes are supposed to do… But if I can screw up like that with my Quirk… Then I'm not going to be great at this Hero thing…"

"A-Ashido, you – "

"I'm not going to be like you."

All noise in the room suddenly seemed to stop. Ashido looked over towards Izuku, to see his eyes wide open in shock, surprise, and other reactional emotions that Izuku himself didn't even know how to describe. It was safe to say that he hadn't expected that sort of response from Ashido, and seemed almost flabbergasted by her answer.

For a while, he didn't know what to say. So Ashido kept talking for him, allowing her own thoughts to unravel through her voice. Once she started, she found herself unable to stop.

"When you first started Yuuei, your Quirk just blew up your arms whenever you used your Quirk. I mean, it was powerful, but you only really could use it once before you were out of it. But you were always really careful with it, and you didn't hurt anyone you didn't mean to with it – Cause you knew how dangerous your Quirk could be. You were careful, and smart. And you learned how to use your power without breaking your bones at all, even if it made the attacks weaker. I… Admire that about you."

"A-Admire?!"

"Mhm. You have a dangerous Quirk, but you can change the way you use it to make it safer. But with mine, it's a lot more difficult…. I mean…. Sometimes I wonder…"

Though he was being hammered by a huge amount of new information that he had to process, Izuku was hanging on every single word that Ashido was saying right now. He had no idea that he was an inspiration to someone that he had barely even spoken to within his class, and while that did, in a small way, make him feel proud of himself…

A small chuckle escaped Ashido's lips, though it was a very quiet one, void of any real humour. "Kirishima'd probably hit me across the face with his Quirk if he heard me say this… I mean, I'm really lucky to have a power like mine, I know. I got born… Really lucky to have a power like mine. I could have been born Quirkless, so I shouldn't complain… But sometimes I wonder if I'm cut out to be a Hero with a Quirk like this."

"Y-You're more than capable of becoming an amazing Hero!"

The response from Izuku had been so instant, so vocal, and so honest that it had surprised even the speaker himself. The words had just tumbled right out, before he'd even thought about what he was saying. He believed every word of it though.

An outburst it might have been, but it was one that he truly did feel genuine passion with.

"You have an amazing Quirk, even if you can't control the Acid that you make! I…. I know what it's like, to feel like you don't really have control over my powers, just like you do. But you're here because you want to be a Hero, right? We're all here because we want to be Heroes! We came here because we wanted to learn how to use our Quirks to become Heroes, and for people like us, that means learning how to use our powers without hurting the people around us that we're supposed to protect. I mean… The fact you rushed me here, just so you could make sure that I got my wound treated – Isn't that proof that you care about people enough to want to help them? Isn't that the first tenant of becoming a Hero?"

His statement, and his short rant, had caused Ashido's eyes to widen this time, and for her focus to have solely fallen onto him. There were no firm or dark expressions anywhere on her face, and the sparkle seemed to have returned to her eyes, almost like they were bringing her back to life. Colour seemed to come back to her face, and a smile seemed to finally make its way back onto her lips, where one belonged.

Neither of the two of them had spoken to the other all that much throughout the year. This much was true, and Ashido knew it perfectly well. They didn't fully understand the other, how their brain worked, or even what they fully thought of the other.

One thing that she was sure about, however, was his honesty, and his passion. Just observing him, even a little since the year started, would help anyone figure out those particular features of the green haired boy. She didn't need to know him on an emotional level to know that he meant every word he said.

He truly did think that she could become a Hero if she tried her best, and didn't give up on herself.

"I – I – I – I - I'm sorry." He rapidly apologized, his face turning bright red in embarrassment at what he had said. He directed his gaze elsewhere, unable to make eye contact with the pink girl, fluster ruling over eyes sense that he had.

Why he felt such embarrassment for stating his stance, Ashido didn't know. But it was endearing.

And moreover… It was inspiring. It was motivational, and it was all true. Nothing that he had said was factually inaccurate in any way, yet it still had so much impact, just through words alone. A short, snappy, and impactful speech born out of emotion and belief, and it had kick started Ashido's belief in herself once again.

Maybe it was because Izuku was the person who was saying it. The one person who would be able to understand the dangers of having a Quirk that was difficult to scale down. Why he felt so strongly about her ability to become a Hero wasn't something that Ashido could fully understand though. It wasn't like they were friends…

Though she knew that it really was just the way that he was as a person.

"…Thanks, Midoriya. I… I needed that." She thanked him, her smile growing brighter and brighter with every passing second. If looks had the power to kill, than the expression that was on her face in that moment would have brought Izuku back to life. "Seriously. Thank you."

Izuku felt his face burning with heat from embarrassment at the praise from the horned girl. Praise and gratitude from girls was still something that he had trouble with, even if he had experienced it a multitude of times since starting at Yuuei. Nervously, he scratched the back of his head with his left hand." U-Uh, no problem."

"You know that hand should still be submerged in water, right?"

"O-Oh!"

Ashido laughed. She and Izuku didn't interact that often, that was true…

But once they had sorted out Izuku's injury, she promised herself that that would change.

* * *

 **This is more an experiment than anything else. Full props for the One Shot idea, and his kind allowance to let me use it does to CoverofThunder – go check out his Dormant Power story. Maybe he'll actually make another chapter. That'd be fun.**

 **This was an interesting experience though. One shots aren't really my sort of thing. I like shorter stories, but this was a good thing for me to do, I feel. It's not really fully romantic, though there were implications. This idea has really just been in my head a lot, for months, so it feels good to finally just get onto paper. It's not like my normal writing style, I feel, but I think it works for the sort of story this is.**

 **This was really just an experiment though, like I said. If you guys like this sort of thing, let me know. Give me ideas for One Shots if you like, and I'll pick out some of the best ones.**

 **This is also possible thanks to the people who support my work on , which helped me justify taking a couple days off schedule to finish this up. Thanks a bunch – If you want to support me (And lemme tell you, I cannot stress the** _ **if**_ **and** _ **want**_ **enough) then consider a donation at QuirkQuartz. You can find a lot more detailed info there.**

 **Once again though, thank you all for reading, and I'll see you next time. See you!**


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